ONS data shows rising toll of climate crisis, with officials warning this summer on track to set further records
More than 40,000 extra people died on the hottest days in England between 1988 and 2025 than would be expected in normal temperatures, according to data published by the Office for National Statistics on Wednesday.
The figures do not include this summer, when England has sweltered under a succession of heatwaves and is on track to record its highest ever number of heat-related deaths. The UK Health Security Agency announced on 30 July that an estimated 2,877 people had died in the May and June heatwaves alone. The total is almost double the figure for the whole summer in 2025.
The number of people dying prematurely due to high temperatures is expected to rise further as the climate crisis caused by the burning of fossil fuels continues to push up temperatures and the population ages. Elderly people, as well as children and the unwell, are particularly vulnerable to heat.
Emergency departments in England’s hospitals have experienced their busiest period ever this summer, with almost 2.5 million patients attending A&E each month in May, June and July and the heat cited as a main reason. Nurses were collapsing during shifts amid “inhumane and impossible” conditions caused by extreme heat, their union warned earlier in August.
London had the highest number of deaths attributable to the hottest temperatures, the ONS said. The London ambulance service has dealt with 25,000 more calls this summer than last, surpassing the record number seen during the peak of the Covid-19 pandemic.
Nearly all English regions, and Wales, experienced a 50% increase in the risk of a person dying when temperatures passed 24C. More than 2,000 deaths in Wales were associated with the hottest days from 1988 to 2025 and 10,000 deaths with the coldest.
Historically, more excess deaths happened on the coldest days than the hottest. There were 139,000 deaths associated with the coldest days in England between 1988 and 2025, according to the ONS data. However, James Tucker at the ONS said: “Our results show that the gap between heat- and cold-related deaths has narrowed in recent years as the proportion of heat-related deaths has increased.”
Dr Clair Barnes, a statistician at Imperial College London investigating the impacts of climate change on extreme weather, said: “We now face the very real prospect of heat deaths overtaking those that occur on the coldest days. As this summer has made abundantly clear, the risk from extreme heat is a fast growing problem that will only worsen without further action to reduce emissions and provide cooling.”
“Many climate change deniers and net zero opponents callously claim that heat-related deaths do not matter because of higher winter deaths, but all these lives matter,” said Bob Ward, of the Grantham Research Institute on Climate Change at the London School of Economics.
“Most of these cold- and heat-related deaths are preventable,” Ward said. “This is a shocking national scandal.”
In the most recent year in the ONS data, the 2,805 heat-related deaths in England and Wales were more than the 2,244 cold-related deaths.
Emma Howard Boyd, the chair of the National Heat Risk Commission, said: “Behind these numbers are people, families and communities. The challenge now is to ensure that our homes, neighbourhoods, infrastructure and public services are better prepared to protect those most vulnerable.”
The UK prime minister, Andy Burnham, has been criticised for a low-key response to the summer heatwaves and the climate crisis, and for moving to cut electric vehicle sales targets and accept new North Sea oil and gas drilling.
Government advisers at the Committee on Climate Change have long warned the country is not prepared for the impact of the climate crisis. The CCC said in May that air conditioning should be installed in all hospitals and care homes within the next 10 years and in all schools within 25 years, and that the government should set a maximum temperature for indoor and outdoor working.
